Fire signal alarm system



1937- I K. LARSON 2,088,708

FIRE SIGNAL ALARM SYSTEM Filed Oct. 8, 1936 2 Sheets-Sheet l 5/ r W F 85 8Q 33 80 f J6 S c 1 I y. ,l r '"l 7 18/5; sea-' l'nveezi'oaw Kasai Lawson,

1937' K. LARSON 2,088,708

FIRE SIGNAL ALARM SYSTEM Filed 001;. 8, 1956 2 Sheets-Sheet 2 .50 temperature.

Patented Aug. 3, 1937 UNITED STATES PATENT OFFICE Application October 8,

11 Claims.

This invention relates to fire signal alarm systems that may be installed at a minimum of expense in homes or other buildings, and which would act with entire certainty to give an audible alarm in the event that the temperature reaches a predetermined extent in the vicinity of the receptacle or container that is provided with metallic members set to contact and establish an electric circuit when said predetermined tem- .10 perature is reached.

In order that the principle of the invention may be readily understood, I have disclosed a single embodiment thereof in the accompanying drawings, wherein- 5 Fig. 1 is a plan view of the receptacle wherein the members of the apparatus or appliance are placed and adjusted;

Fig. 2 is a vertical section. thereof upon the line 2-2 of Fig. 1;

20 Fig. 3 is a horizontal longitudinal section thereof upon the line 3-3 of Fig. 2;

Fig. 4 is a vertical transverse section on the line 4-4 of Fig. 2; and

Fig. 5 is a diagrammatic View indicating the 25 said receptacle and wiring extending therefrom to a plurality of audible signals.

I am aware that it has heretofore been proposed to install fire signal alarm systems in dwellings or other buildings, but such devices are 30 relatively complicated and expensive, and moreover can be readily tampered with, so: that they will not function properly or with certainty.

, In accordance with my invention, I provide a fire signal alarm system having as a part thereof 35 a receptacle that receives the metallic. wires or rods that are so set that their ends contact when a certainpredetermined temperature is reached and thereby sound the alarm, and which wires or rods cannot be adjusted or altered in their rela- 40 tionship to each other after their purchase or installation.

'Without limiting myself to the exact construcjtion shown, I will describe one embodiment of "means for practising my invention.

45 I provide a suitable receptacle indicated at I "in the several figures of the drawings. It is preferably a six walled receptacle composed desirably throughout of some material that is not acted upon or readily acted upon by changes in Preferably the walls of the receptacle are composed of bakelite or some other material having the property of being non-responsive to changes in temperature within usual limits. After careful study I have determined that for 1936, Serial No. 104,598

best results a temperature of 110 degrees Fahrenheit is the most suitable temperature at which to cause the system to operate, but it is to be understood that I am not limited to any precise or certain temperature, as I leave this to the decision of the one intending to purchase the apparatus or system and who will thereupon have the apparatus so set or adjusted, and sealed or looked, that it cannot thereafter be tampered with but will respond accurately if and when the decided upon temperature is reached.

As shown in Figs. 1 to 4, the upper and lower walls 2 and 3 of the receptacle I are provided With openings 4 which permit circulation of air therethrough. The receptacle has end walls 5, 6 which are shown as having openings I for the wiring. I provide means for securing the receptacle I in position upon a wall of the building, and for that purpose I have shown integral extensions or ears 8 having holes 9 adapting the receptacle to be secured by screws upon the wall or other support. It is to be understood that if desired more than one receptacle I may be provided in a single building, each responsive to heat conditions in its own area or zone of action. Each receptacle, however, should have its own circuit and each such circuit may include any suitable number of bells or other audible alarms, two of which are represented at I0, I I, in Fig. 5. Desirably I place one of said alarms I0 upon the outside of the building (that is, upon an outer wall thereof), and I may have as many similar audible alarms inside the building all in the same circuit as desired. For best results, there should be an audible alarm II in each room of the building.

The receptacle I, if only one is provided, should be placed for best results near or over the furnace,

as that is the point where the greatest danger of fire exists.

The receptacle I, the forms and size of which may obviously be varied within the scope of my invention, should for best results be mounted as near to the ceiling as possible, that being normally the hottest point in a room. If hung in the furnace room, the contents of the receptacle I will become warmed or heated to a functioning temperature before the woodwork etc. start to burn. Preferably also, one of the receptacles is mounted at the top of the stairs leading to each floor, since the heat and smoke, in case of fire, usually follow these passageways, which serve as flues.

In order to provide complete protection, I prefer to place one receptacle I with its own circuit on each floor of the building, since each receptacle will function only if there be a fire in its own area or zone. For example, if a fire should break out in the attic and no receptacle I is 5 provided there, there would be no alarm even though there were a receptacle in the furnace room.

A sprinkler system usually functions at a tem perature of 135 F., and necessarily causes much damage. My apparatus or system functions at 110 or thereabouts, depending upon the setting thereof, before the fire can make any headway, and causes no damage whatever. Moreover, it can be very inexpensively installed, since the receptacle I may be of quite small size, as for example, five inches in length, and it and its contents can be sold at a price of about one dollar.

Referring more particularly to Figs. 2 and 3, I have therein represented two wires or rods l2, l3, each preferably of general V shape. As shown, they have vertical members I4, I5 received respectively upon screws l6, II that are themselves entered through suitable openings in the end walls 5, 6 of the receptacle I. The said members |4, |5 are bent as indicated to encircle the screws I6, l1, and I provide two nuts I 8, l9, and 2|, 2| respectively for each of said wires or rods l2, I3, positioning them as shown on each side of the bent ends of the members l4, l5 thereof. I also provide nuts 22, 23 between which and the nuts I9, 20 respectively, are secured the i ends of wires 24, 25 of the circuit which, as shown,

includes a transformer 26 and wires 21, 28 lead- .35 ing to any suitable source of electricity, as, for

example, the main or lighting circuit of the buildmg.

The wires or rods |2, |3 are also provided with inclined members or portions 29, 3|] terminating in ends 3|, 32, which by the means to be described are fixed at a predetermined distance apart so that when the temperature rises to the predetermined extent said ends contact and complete the circuit and sound all the alarms that are in l said circuit.

The distance apart at which the two ends 3|, 32 are set depends not only upon the temperature decided upon as the one at which the alarm shall be given, as, for example, 110 degrees Fahrenheit, but also upon the length and diameter of the wires or rods 29, 30, it being well known that the longer the wires the greater will be their expansion at any temperature.

In order to set the rods 29, 30 with their ends 3|, 32 spaced apart to precisely the right extent,

I have provided the following simple but effective means, preferably employed by me but to which my invention is not limited.

A tie rod or tension wire 33 of any suitable material extends through both of the end walls 5, 6. It is secured in the wall 6 without capacity for adjustment, it being shown as threaded at 34 and receiving nuts and washers 35 for securing the same fixedly in the said wall 6. At its opposite end the said rod or wire 33 is also threaded and upon its end outside the receptacle it receives a washer 36 and one or more nuts 31. The construction is such that the walls 5, 6 may be drawn slightly toward each other by turning one or more of the elements on said rod or wire exterior to the wall 5. This setting or adjustment is intended to be done by the one selling or installing the apparatus or system, and he makes the setting or adjustment so that the end 3|, 32 of the rods or wires 29, 30 will touch and complete the circuit when the precise predetermined temperature is reached. This setting should be very accurately done and the testing should be made with a Fahrenheit thermometer. Preferably after such setting or adjustment has been accomplished, the parts should be sealed or locked in some suitable manner so as to prevent tampering. For this purpose, I have, in Figs. 1, 2, 3, represented solder 38 as applied in suflicient quantity over the end of the rod or wire 33 where the same extends through the nut 31, thus preventing any turning thereof. I am, however, not limited to such looking or sealing means, some form of which I, however, preferably employ.

While the rods or wires 29, 30 may be of any suitable material, I preferably form them of copper. By forming the rods 29, 30 of the shape shown, they lean or are inclined toward each other and if there be any sagging or yielding of said wires after prolonged use, they would tend to contact with each other and sound an alarm rather than to sag away from each other and so be ineffective when they should act.

While this might result in a false alarm, it is obvious that it would be far preferable to have a false alarm occur than to have the device ineffective when the real need therefor occurs.

Having thus described one illustrative embodiment of the invention, it is to be understood that although specific terms are employed, they are used in a generic and descriptive sense and not for purposes of limitation, the scope of the invention being set forth in the following claims.

I claim:

' 1. In a. fire signal alarm system, a receptacle the walls whereof are substantially unaffected by temperature changes, a tie or tension rod connected to a pair of opposing walls thereof and having adjusting means for varying the spacing of said walls, and a pair of opposing metal rods mounted in said walls and having ends extending into such proximity to each other that upon temperature rise to a predetermined extent they contact to complete an electric circuit, whereby an alarm may be given.

2. In a fire signal alarm system, a receptacle the walls whereof are substantially unaffected by temperature changes, a pair of opposing metal rods expansible by reason of temperature increase and respectively supported by two opposite walls of said receptacle, the ends of said rods extending into such close proximity to each other that when the temperature rises to a predetermined extent they contact to complete an electric circuit, and means for flexing said walls toward or from each other so as to vary the spacing between the ends of said rods.

3. In a fire signal alarm system, a receptacle the walls whereof are substantially unaffected by temperature changes, a pair of opposing metal rods expansible by reason of temperature increase and respectively supported by two opposite walls of said receptacle, the ends of said rods extending into such close proximity to each other that when the temperature rises to a predetermined extent they contact to complete an electric circuit, means for flexing said walls toward or from each other so as to vary the spacing between the ends of said rods, and means to seal said flexing means to prevent subsequent adjustment thereof.

4. In a fire signal alarm system, a receptacle the walls whereof are substantially unaffected by temperature changes, a pair of opposing metal rods expansible by reason of temperature increase and respectively supported by two opposite walls of said receptacle, the ends of said rods extending into such close proximity to each other that when the temperature rises to a predetermined extent they contact to complete an electric circuit, said rods each being of substantially V shape with their inner ends upwardly inclined toward each other.

5. In a fire signal alarm system, a receptacle the walls whereof are substantially unaffected by temperature changes, a pair of opposing metal rods expansible by reason of temperature increase and respectively supported by two opposite walls of said receptacle, the ends of said rods extending into such close proximity to each other that when the temperature rises to a predetermined extent they contact to complete an electric circuit, each of said rods being of substantially V shape, a tension rod connecting the walls of the receptacle wherein said metal rods are mounted,

and means for adjusting said tension rod.

6. In a fire signal alarm system, a receptacle the walls whereof are substantially unaffected by temperature changes, a pair of opposing metal rods expansible by reason of temperature increase and respectively supported by two opposite walls of said receptacle, the ends of said rods extending into such close proximity to each other that when the temperature rises to a predetermined extent they contact to complete an electric circuit, each of said rods being of substantially V shape, a tension rod connecting the walls of the receptacle wherein said metal rods are mounted, means for adjusting said tension rod, and means to seal said tie rod in adjusted position.

7. In a fire signal alarm system, a receptacle the walls whereof are substantially unafiected by temperature changes, a pair of opposing metal rods expansible by reason of temperature increase and respectively supported by two opposite walls of said receptacle, the ends of said rods extending into such close proximity to each other that when the temperature rises to a predetermined extent they contact to complete an electric circuit, and a tension rod connected to said two opposite walls of the receptacle to flex said walls toward and from each other, to vary the spacing between the ends of said rods.

8. In a fire signal alarm system, a receptacle the walls whereof are substantially unaffected by temperature changes, a pair of opposing metal rods expansible by reason of temperature increase and respectively supported by two opposite walls of said receptacle, the ends of said rods extending into such close proximity to each other that when the temperature rises to a predetermined extent they contact to complete an electric circuit, a tension rod connected to said two opposite walls of the receptacle, to flex said walls toward and from each other, to vary the spacing between the ends of said rods, and means to seal said tension rod in determined position.

9. In a fire signal alarm system, a pair of opposing metal rods expansible by reason of temperature increase, a support for each of said rods, such support being substantially unafi'ected by temperature changes, the ends of said opposing metal rods extending from their respective supports into such close proximity to each other that when the temperature rises to a predetermined extent, they contact to complete an electric circuit, and tensioning means for moving said supports under tension toward or from each other, so as to vary the spacing between the ends of the said metal rods.

10. In a fire signal alarm system, a pair of opposing metal rods, each of substantially V shape with their inner ends upwardly inclined toward each other, said rods being expansible by reason of temperature increase, a support for each of said rods, such support being substantially unaffected by temperature changes, the ends of said rods extending into such close proximity to each other that when the temperature rises to a predetermined extent, they contact to complete an electric circuit, and. means for tensioning said supports slightly toward and from each other, thereby to vary slightly the distance between the ends of said rods.

11. In a fire signal alarm system, a pair of opposing metal rods expansible by reason of temperature increase, a support for each of said rods, such support being substantially unaffected by temperature changes, the ends of said opposing metal rods extending'from their respective supports into such close proximity to each other that when the temperature rises to a predetermined extent, they contact to complete an electric circuit, and a tension rod connected to the said supports to move them toward and from each other, thereby to vary the spacing between the ends of said metal rods.

KNUT LARSON. 

